Continuous automatic flexible conveyer



Jan. 1, 1957 c. H. SNYDER CONTINUOUS AUTOMATIC FLEXIBLE CONVEYER 5Sheets-Sheet 1 Filed March 27, 1952 Jan. 1, 1957 c. H. SNYDER 2,776,040

CONTINUOUS AUTOMATIC FLEXIBLE CONVEIYER Filed March 27, 1952 5Sheets-Sheet 2 Jan. 1, 1957 c. H. SNYDER 2,775,040

CONTINUOUS AUTOMATIC FLEXIBLE CONVEYER Filed March 27, 1952 5Sheets-Sheet 5 Jan. 1, 1957 c. H. SNYDER CONTINUOUS AUTOMATIC FLEXIBLECONVEYER 5 Sheets-Sheet 4 Filed March 27, 1952 MNN WNN

W N mow m Jan. 1, 1957 c. H. SNYDER CONTINUOUS AUTOMATIC FLEXIBLECONVEYER 5 Sheets-Sheet 5 Filed March 27, 1952 INENTOR.

fiiiifoelvzx United States Patent CONTINUOUS AUTOMATIC FLEXIBLE CONVEYERClifford H. Snyder, Dormont, Pa., assignor to The Colmol Company, NewLexington, Ohio, acorporation of Ohio Application March 27, 1952, SerialNo. 278,940

2 Claims. (Cl. 198-92) This invention relates generally to conveyers andmore particularly to a conveyer system supported on a flexibly coupledtrain of self-contained vehicular units attached to a mining machine toreceive and convey material therefrom, and wherein each successive unitof the moving train is steered at the same relative-position that themining machine changed its course and the units of the train thus followin the same path.

It has been common practice to use shuttle cars and shuttle trains totransfer coal in tracltless coal mines. The principle involved in bothinstances requires the loading, the hauling, and the unloading of theshuttle device, which is required whether theshuttle device is a simplecar,- or a train of cars. The shuttle train may be loaded at one end andunloaded at the other end; It may be steeredas a train from either end.The answer to the problem of steering and propelling a tracltless.

train comprising a consecutive series of fouror twowheeled vehicles, hasbeen suggested by the use of several different structures.

None of these former structures will operate satisfactorily'for removingmaterial suchas'coal from a continuous mining'machine. The greatestdifiiculty'is that the continuous mining machine has to be stopped topermit the shuttle device to carry its load away from the continuousmining machine and another shuttle device to take its place. productionof coal. The interruptioncaused by changing shuttle devices producesadditional problems in the continuous mining machine operation, as wellas presenting problems in haulage space and-spillage.

The principal object is the provision of a conveying train that avoidsthese difficulties by attaching the conveyer train to the continuousmining machine while being used so that the guiding and operation ofthemining machine guides and operates the conveyer train.

To operate continuously, the mining machine and conveyer train must besupplemented by a main haulageor conveying system, the loading portionof which may extend for substantially the full length of the train. Sucha main haulage system may be a continuously moving belt, a pneumaticsystem or a second. or repeated conveyer train that extends to a tippleor other receiving device and capable of continuously handling, thecoal. The receiving device such as this-must be capable of being readilyextended into the mine as the mining progresses.

The mining machine cuts entries and rooms laterally from a main haul orentry which has a material receiving device, such as a belt conveyer.Break-throughs are then cut to interconnect the entries and rooms as themining progresses in the ordinary manner. The intermediate conveyertrain trails the mining machine through th circuitous path inprogressively mining.

If it is necessary to withdraw from one room or entry to form the nextconsecutive room or entry, the whole of the train, and the miningmachine, may be reversed as a unit, or the conveyer train mechanism may.be re- Suchstoppage materially reduces they Patented Jan. 1, 1957structures may be adapted for the purpose of supporting this invention.

Other objects and advantages appear hereinafter in the followingdescription and claims.

The accompanying drawings show for the purpose of exemplificationwithout limiting the invention or claims thereto, certain practicalembodiments of the invention, wherein:

Fig. l is a plan viewof a continuous mining machine having a train oftwo-wheeled vehicular cars supporting a single drag conveyer.

Fig. 2 is an enlarged view of an intermediate portion of the-conveyershown in Fig. 1.

Fig. 3' is an enlarged view illustrating the portion of a conveyer trainhaving a single belt conveyer.

Fig. 4 is a view of the structure shown in Fig. 3 at a corner.

Fig. 5- is an enlarged plan view'of a roller bumper for use on a cornerin a mine.

Fig. 6 is a view in side elevation of the structure shown in Fig. 5.

Fig; 7 is a view inside elevation of a corner bumper structure engaginga portion-of aconveyer train.

Fig. 8 is a plan view of the tender side of a conveyer train made up ofa series of four steerable wheel vehicular structures and employing anendless belt conveyer.

Fig. 9 is a plan view of the receiving unit of another form of vehicularconveyer train.

Fig. 10* is a plan view of the under side of an intermediate unit of theconveyer train for the receiver of Fig. 9.

Fig. 11 is a view in sideelevation of the structure shown in Fig. 9.

Fig. 12 is asectional view showing the junction of two vehicularsections. of the conveyer train units of Figs. 9 and 10.

Fig. 13-is.a side view in elevation of the discharge unit of theconveyer train.

Fig-.14 is a plan View of the discharge unit shown in Fig. 13-.

Fig. 15 is an enclosed sectional view taken in the line 15-15-of- Fig.14'. a

A mining operation is illustrated diagrammatically in Fig. l, wherein 1indicates the mining machine, which is mining in a secondary entry, anda conveyer train 2 extends therefrom to a position in the main entry inwhichis installeda belt conveyer such as illustrated at 3.

The conveyer train. Zis provided with a receiving end 4, conveyer traintraction means as indicated at 5, and the discharge end- 6 having atraction means 7, and an articulated boom 8 for directing the materialfrom theendless conveyer 10, to the endless conveyer 3, from whence itis conveyed in the direction as indicated by the arrow to the tipple ofthe mine.

The conveyer train 2 is made upof receiving and discharge members 4-and6-with traction means andeither of which can guide and draw the conveyertrain through the mine, independently of the mining machine 1, however,the receiving structure 4 is attached to the mining machine 1, and whenthe latter is operated to move forward, the samecontrol functions toactuate the traction members Sand 7 to move the conveyer forward as aunit.

Although the conveyer train trails the mining machine, it may be made tosupply it own propulsion energy, and is provided with motors for thispurpose.

The intermediate sections of the conveyer train 2 are comprised oftwo-wheeled vehicles pivoted intermediate of their ends to each other,as indicated at 11, and these vehicular members are provided with theframe which supports a flexible structure such as illustrated at 12,which is a double deck member arranged to carry an endless drag conveyersuch as illustrated at 13 in Figs. 1 and 2. This endless drag chainconveyer extends from the forward end of the conveyer train, beingpositioned-underneath the conveyer 13' of the mining machine and toreceive the coal and transport the same between the flexible sides tothe rear of the train and over the swinging beam 8 where it is finallydeposited onto the endless belt conveyer, 3. 4

The two-wheeled vehicular units of the conveyer train may not exactlyfollow the previous car when being trailed, and may be required to havesome form of bumper means on the corners of themine, to maintain thecars in proper alignment. Such a bumper structure is illustrated at 14in Fig. l, and is also on the corners, as illustrated at 15 in Figs. 6and 7, which have a series of vertical shafts 16 for rotatablysupporting the pulleys 17 of which five are shown. The support 15 isplaced on the floor of the mine, and is held in place by'the roof jacks,such as illustrated at 18. The roof jacks may be vertical or they may bedisposed at an angle, such as indicated by the dotted line 19.

The pulleys 17 may engage the cable member 20 such as illustrated inFig. 1, which is on the sides of the conveyer train, and which aresupported by spaced eyes on the outer ends of the brackets indicated at21 in Fig. l. The cable 20 will engage the pulleys and prevent thewheels from hampering the progress of the conveyer train.

In the structure shown in Fig. 2, the cable 20 is woven 7 between thepulleys rotatably carried by the vehicular structures as indicated. Thecable 20 is held by the pulleys 22 on both sides of the vehicular wheels23 and in back of the pulleys 24 which are intermediate of the vehicularwheels 23. In this way, the cars of the trains maintain their spacedposition regardless of the articulated angle that the conveyer trainmust pass in following its path. The cable 20, together with the pulleys22 and 24 engage the pulleys 17 on the center of guide posts at thecorners of the mine for the purpose of aiding the movement of theconveyer train through its circuitous path in the mine.

In the structure as shown in Fig. 3, the cable member 20 has beenreplaced by the frame 25 that completely surrounds the vehicular memberand is cut away adjacent the pivotal point between the vehicular membersso that they may negotiate a curve such as illustrated in Fig. 4. Thesides of the conveyer trough 26 of this structure, are flexible and arelikewise made as a double deck so as to receive the upper and lowerflights in this conveyer such as indicated at 27.

Referring now to Fig. 8 which shows the underside of a conveyer trainmade up of a series of four steerable wheeled vehicle structures, andwhich comprises the car units 30 having the axial members 31 on which ismounted the steerable wheel 32. The arms 33 of the steerable wheels areconnected by the rod 34 to the pivoted tongue 35. The pivoted tongue 35has a vertically movable extension bar 36 which is pivotally supportedby the pin 37, to the tongue member 35, that is pivoted on the axle, asindicated at 38.

Each of the steering mechanisms and each of the units are identical, andone of each pair of wheels is provided with an arm 40 which is connectedby the adjustable reach rod or steering rod 41. The cars may thus beindependently steered by the preceding car. Since the extension memberbar 36 is non-flexible, and has a vertical pivot connecting it with eachof the ends to pivoted tongue members 35, when the first car is causedto deviate laterally by reason of the extension 36 being pulled in thedirection of the deviation, the wheels are caused to turn, and theturning of the Wheels likewise turns the rear wheels. At this time, thebody begins to turn and follow the previous car. However, since the bodyis turning, and the wheels have likewise turned relative thereto, thenext succeeding extension bar 36 has not been effected to turn the frontWheels in the next succeeding car until they have arrived at the sameposition as that of the rear wheels of the previous car. This occurswhen the body of the previous car has completely followed its lateralpath, and wheels, let us assume, are again parallel with the body. Underthese conditions, the tongue of the next succeeding car is swerved inthe same lateral direction, at which time, the body starts to follow thesame devious path, and produces the same effect on the rear wheels ofthat car. Similar structures of this character are shown in the priorart as previously mentioned.

The bodies 30 of the cars of this train are overlapped, and each isarranged to support an endless belt conveyer, and is provided with amotor for producing the propulsion of the train and a drive for theconveyer. A detailed structure of this character is disclosed in thefollowing drawmgs.

Referring now to Fig. 9, wherein is shown the understructure of theintermediate car of a train of cars, the steering of which is somewhatsimilar to the structure as shown in Fig. 8, but in greater detail, andthe receiving unit of this train includes a rather low, generallyhorizontal elongated main frame 40 which is fabricated fromlongitudinally, transversely and angularly extending channels, angles,plates, and the like, all welded or otherwise attached rigidly together.Adjacent its receiving end, the main frame 40 is constructed to form ahopper 41 which is adapted to receive material, such as coal, whichdischarges over the discharge boom of the associated mining machine,such as a continuous mining machine 1 or a loader. The hopper 41preferably has a wide open bottom which is normally closed by thereceiving end of the load carrying run of a continuous rubber fabricbelt. The somewhat similar conveyer belt for the intermediate unit isillustrated in Figs. 10 and 11 of the drawings. The lateral sides of thebottom of the hopper 41 are provided with longitudinally extendingstrips 43 of rubber belting, or the like, which overlap the receivingbelt an appreciable amount so as to reduce spillage of material from thehopper to a minimum.

The endless rubber belt 44 which conveys material such as coal, from oneend of the frame 40 to the other, and discharges it into the receivingend of the following intermediate unit of the system, extends from atail pulley 45 over hopper idler 46 and a plurality of troughing idlers47 placed at longitudinally spaced positions along the frame 40'to ahead or discharge pulley 48. The return run of the belt 44 extendsrearwardly from the head pulley 48 around an adjustable take-up and bendpulley 49 thence forwardly around a drive pulley 50, thence rearwardlyover return idlers 51 spaced at appropriate intervals longitudinallyalong the frame 40.

The drive pulley 50 is driven from an electric motor 52 which is mountedadjacent one side of the main frame 40 and preferably laterally outsidethe adjacent main longitudinally extending frame member thereof. Motor52 is connected to the drive pulley 50 through a speed reducer 53 andappropriate chain and sprocket drive mechanism 54.

Adjacent one side and generally at the center of the main frame 40 thereis an operators station at which there is a control box 55 forcontrolling the motor 52, as well as also simultaneously controlling allthe conveyer belt motors of the entire system. There is an auxiliarycontrol box which may be extended to the associated mining machine sothat starting and stopping of the v conveyer belts of the intermediatesystem may be there controlled. 4

Adjacent the receiving end the receiving unit is provided with a hitch57 which is pivotally attached to the frame of the associated miningmachine 1 by a bracket 58 and a transversely extending horizontal pivotpin 59 about a transverse horizontal axis relative to the associatedmining machine 60; the hitch otherwise being held against movementrelative thereto.

The hitch 57 is provided with a universal joint 61 which is in generalalignment with the longitudinal center line or axis of the main frame40. As a consequence of this connection, the forward end of the hitch 57is connected by a universal joint to the tongue 62.

The conveyer unit 40 is provided with two pairs of supporting andsteering wheels at each end thereof. As clearly illustrated in thedrawings, each pair of wheels designated at 66 preferably includespneumatic tires. The wheels 66 are mounted for steering and are mountedon individual king pins for steering adjustment the king pins beingcarried on brackets rigidly attached to the frame.

The wheels 66 are steerable, and to this end they are provided with theusual steering mechanism 73, best illustrated in Fig. 9 of the drawings,which steering mechanism includes a conventional manually operablesteering wheel 74.

In Fig. 9 of the drawings there is illustrated, among other things, themanner in which the receiver or two units of the conveyer system aremechanically coupled together for articulated movement relative to eachother, particularly about an upright axis along their center lines. Theconnection also provides a limited amount of universal movement betweentwo interconnected'units. The main frame 40 includes a V-shaped topcross-pieces}, the apex of which is substantially at the longitudinalcenter of the unit. This-cross-piece 83' is provided adjacent said apex,with at least a portion of the universal joint type connection similarto that hereinafter described in connection with Fig.9.

Eachintermediate unit includes a main frame 84 constructed similarly tothe receiving unit. As shown in Figs. and 11, the frame forms a shallowreceiving hopper 85 which is adapted to receive the material di'schargedover the pulley 48 of the receiving unit 40. The two sides of the hopper85 are provided with a-flexible material guide 86 preferably made ofrubber belting, or the like, which guides the material into the upper orload carrying run of an endless rubber belt 87 carried by the unit 84,and extending from the tail pulley 83-to thehead pulley 89. The upper orload carrying run of saidbelt 87 is supported by a plurality oflongitudinally spaced troughing idlers 90-. There is also a materialsupporting idler 91 for supporting the upper run of the belt 87 adjacentthe hopper 85.

ing controlled by the preceding unit, whether it be a receiving unit, orintermediate unit, and in turn passing the steering control onto thesucceeding intermediate or discharge unit, as the case may be.

On each unit of the train, there is a pair of power driven and tractionsteerable wheels 98, each preferably including a pneumatic tire. Thewheels 98 are mounted upon king pins for steering adjustment but areheld against up'and down movement relative to the main frame 84. Toprovide the power or traction drive to the two wheels 98, a tractionelectric motor 99 is carried on one 6 side of one of the upright framemembers of frame 84 and extends to a speed'reducer 100.

As best illustrated in Fig. 11 of the drawings,- a drive shaft 101extends from the speed reducer 100 both upwardly and downwardly, saiddrive shaft 101 carrying a drive sprocket of a chain and sprocket drive102-, which drives a vertical shaft 103, which in turn drives a bevelgear 104 meshing with a bevel gear 105 rigid with one of the wheels 98.The lower end of the shaft 101 is provided with a bevel gear 106, whichmeshes with another bevel gear 197, which drives a cross shaft 108provided with appropriate universal joints. The cross shaft 108 drivesan upstanding "shaft 109 through appropriate spur gears, which shaft 109is provided at its upper end with a chain and sprocket drive 110 whichin turn drives the other wheel 98 through mechanism which issubstantially duplicated with that just described in connection with thefirst wheel 98.

pin, or to receive a portion bar 113 of a telescoping hitch which isused to interconnect two adjacent intermediate Lmits or to connect anintermediate unit and the receiving or discharge unit.

Units 40 and 84 are supported by a pair of independentlyspring-suspended wheels 114 preferably provided with pneumatic tires andmounted for steering a'djustment in a more or less conventional manner.The suspension mechanism for each of the wheels 114 includes a pivotedarm 1:15 pivoted at its inner end to a ce'nter casting 116 constitutinga rigid part of the main frame 84.- The outer end of the arm 115 carriesthe king pin and axle bracket for the wheel.

Extending through a bifurcated portion of each pivoted arm 115 andthrough a wing of the casting 116' is an individual elongated torsionrod 117 which adjacent its forward end is splined to a keeper arm 118which is bolted to the pivoted arm 115. It is evident that each torsionrod 117 provides a pivotal connection between a wheel supporting arm 115and the center casting 11.6 of the main frame 84. Each of the torsionrods 117 extends rearwardly to the rear cross axle, upon which the rearwheels 98 are supported and is splined to a keeper arm 119 bolted tosaid rear axle. The torsion rods 117 extend through appropriate holes insaid rear axle adjacent their splined connection to' the keeper arms 119shown in Fig. 10.

The front wheels 114 are provided with steering link mechanism 120'generally similar to the steering link mechanism 111, includir'1g abracket or tongue casting 121 which is preferably a duplicate of thetongue casting 112. The two steering link mechanisms 111 and 120 arepreferably coupled together by steering link mechanism 122, said linkmechanism 122 causing the wheels 114 to turn oppositely from the wheels98.

Adjacent the front end of the unit, there is a hitch element 123 whichis pivotally attached to the bracket or casting 121, and which iscomplementary to the hitch element 113 and cooperates therewith toextend the steering control from the receiving unit, as above described,through each intermediate unit and ultimately to the discharge unit.

Adjacent its rear end the intermediate unit is provided with a V-typecross piece 124 and adjacent its front end there is a generally similarV-type cross-piece 125. The cross-pieces 124- an'd 125 arecomplementary, as hereinafter described, to a similar pair of connectingmembers in connection-with an intermediate and discharge unit end of thefirst intermediate unit and the cross-piece or bracket 124 of the secondintermediate unit, if present, or if not present, between the bracket125 or the intermediate unit and a similar bracket, hereinafterdescribed at the rear of the discharge unit.

From the description, it is to be noted that each of the units have fourwheels and are power driven, and thus constitute at least part of thetraction means for the complete conveyer system and is provided withmechanism whereby all of the supporting Wheels are steerable, thesteering being controlled automatically normally by the receiving unitwhen going forward or on the alternative by the discharge unit whengoing backward, or as hereinafter described, by the discharge unit.

Attention is now directed particularly to Figs. 13 and 14 and to theconstruction of the discharge unit. Except for such differences as areobvious, or are pointed out, it is to be understood that the dischargeunit is similar to the intermediate unit just described. Without goinginto too much detail, it may be stated that said discharge unit includesa main frame, 126. The main frame is supported upon pairs of front andrear interconnected steerable wheels which are attached by theillustrated hitch to the preceding intermediate unit. Said dischargeunit is provided with an endless conveyor belt 127, driven by anelectric motor 128. The driving roller, supporting idlers, and otherelements of the discharge unit are essentially similar to those of theintermediate unit. It will be noted however, that, unlike theintermediate unit, none of the wheels of the discharge unit is powerdriven. Likewise, unlike the intermediate unit, there is a manualsteering control cylinder 129 associated with the interlocking steeringmechanism which may be controlled by one of the valves of a bank ofhydraulic valves 130 which control various hydraulic motors of thedischarge section, as hereinafter described more completely. Asillustrated in Figs. 10 and 12 of the drawings, the bank of valves 130is provided with a plurality of control rods and levers, whereby eachvalve may be operated from either side of the unit.

The discharge unit also carries an electric motor 131 driving ahydraulic pump 132 for providing hydraulic fluid to actuate the severaladjusting motors on said dis charge unit. The discharge unit does nothave any torsion rods comparable with the rods 117 of the intermediateunit, but the wheels are mounted for vertical adjustment by mechanismquite similar to that provided 7 for the intermediate unit. Said wheels,however, are

vertically adjustable about their inward pivot points by means of adouble acting hydraulic piston motor 133. The piston rod and cylinder ofsaid motor 133 are connected to opposite ends of the wheel arms asclearly illustrated in Fig. of the drawings.

Adjacent the end of the main frame 126, the discharge unit is providedwith a cross-piece 134 which is comparable in structure with thecross-piece 125 of the intermediate section. Extending forwardly fromthe front of the discharge unit and forming a part thereof is adischarge boom 135 which is formed in two sections namely, the rearreceiving section 136 and a front discharge section 137.

As best illustrated in Figs. 13 and 14 of the drawings, the entiredischarge boom 135 is mounted for swinging movement about an uprightaxis relative to the front portion of the body proper of the dischargeunit. This swinging connection is provided by top pivot means 138 whichpivotally connects the aforementioned crosspiece 134 and a cross-piece139 forming part of the frame of the rear portion 136 of the boom 135.Adjacent the bottom of the frame of the receiving section 136 there isalso a pivot connection which is in alignment with the pivot connection138. These pivot means provide for swinging movement of the entire boom135 about an upright axis along the longitudinal center line of thedischarge unit.

Mounted on the two sections 136 and 137 of the boom 135, there is anendless belt 141 which travels over appropriate tail, head, bend, anddrive pulleys, and is supported by appropriate idlers, all as clearlyillustrated in Figs. 13 and 14, of the drawings. The belt 141 willreceive material from the belt 127, and dis-. charge it over the headpulley of the boom onto a receiving belt conveyer or any otherreceptacle, or merely onto the ground.

The receiving section 136 of the boom 135 carries an electric motor 142which drives the drive pulley thereof through appropriate drivemechanism illustrated particularly in Fig. 13 of the drawings. Thedischarge section 137 of the discharge boom 135 is mounted foradjustment on a transverse horizontal axis provided by pivot means 143,this adjustment being controlled by a double acting hydraulic pistonmotor 145, the cylinder of which is pivoted to the main frame 126, andthe piston of which is pivotally attached to an operating arm carried bythe frame of the receiving section 136 of the discharge boom 135.

The various hydraulic motors of the discharge unit, including thesteering motor 129, Fig. 10, the wheel adjusting motor 133, Fig. 13, theboom swinging motor 145, and the motor for adjusting the dischargesection 137 of the boom 135 are controlled by individual lines to thehydraulic valves 130. All of these cylinders are double acting and arelocked in their normal positions of adjustment. The valve which controlscylinder 129 also has a fourth position in which this cylinder isallowed to float freely. This is required, of course, when the steeringof the discharge unit is controlled by the adjacent intermediate unit.

The discharge end of the discharge unit may be raised and lowered bycontrolling the motor 133. In addition, the final discharge pulley,namely, the discharge pulley of the discharge section 137 of thedischarge boom 135, may be raised and lowered by the cylinder 144.

Attention is now directed particularly to Fig. 12 of the drawings wherethere is illustrated in some detail the overlapping of any two adjacentunits, which may be either the receiving and the intermediate units, theintermediate units themselves, or an intermediate unit and the dischargeunit. In the particular illustration, the last intermediate unit isshown discharging into the discharge unit.

As clearly illustrated, the belt 87 of the intermediate unit overlapsthe belt 127 of the discharge unit. It is therefore obvious thatmaterial being conveyed, such as coal, will drop a relatively shortdistance from the belt 87 and be received by the belt 127 and carried onto be received by the discharge boom belt 141 from which it will bedischarged into a receiving room conveyer, or the like.

The main frames of the intermediate and discharge units are connectedtogether by means of a ball and socket joint or connection 146 whichinterconnects the cross-piece of the main frame 84 of the intermediateunit with a similar cross-piece 147 at the rear and top of the unit 126.The ball and socket connection 146 provides articulated or free swingingmovement between the two conveying units on an upright axis, and inaddition, it provides for limited movement between said two units onhorizontal axes. In other words, it is a limited universal jointconnection. The steering control is transferred from the intermediateunit to the discharge unit by means of the hitch 123, 113, which twotelescoping parts provide for relative longitudinal movement between thetwo units.

The length of the conveyor system may be adjusted at will by controllingthe number of intermediate units.

The mining machine 1 may have a conveyor train attached to it whichfollows it over a circuitous path through the various entries,break-throughs, and rooms, receiving the output from the mining machine,and delivering it over the discharge boom 135 onto a main entry orreceiving conveyer 3 which may, for example, be an endless belt conveyerin the main haulage entry of the mine, as shown in Fig. 1.

The discharge boom may swing laterally to discharge the material ontothe conveyer 3. The conveyer system follows along the receiving conveyerand is parallel therewith for a significant distance, then winds througha break-through, continuing to the rear end of the mining machine 1. Itis evident that the mining machine can proceed in any direction to anappreciable distance from the position illustrated before it will beimpossible for the discharge boom 135 to discharge the coal onto thereceiving conveyer 3. When that condition is realized, it is usuallynecessary to extend the receiving conveyer 3.

By virtue of this important link between the continuous mining machineand the main entry or receiving conveyer 3 it is possible for the miningmachine 1 to operate in a continuous manner substantially withoutstopping. Furthermore, it is entirely practical for the mining machineto back up as the traction motors for the intermediate conveyers arereversible and are all controlled from a central control station.

Those skilled in the art may make various changes in the details andarrangements of parts without departing from the spirit and scope of theinvention as defined by the claims hereto appended, and applicanttherefore wishes not to be restricted to the precise construction hereindisclosed.

Having thus described and shown an embodiment of 10 the invention, whatit is desired to secure by Letters Patent of the United States is:

1. A flexible conveyor having at least three tandem conveyor supportingunits, including a receiving unit, a discharge unit, and at least oneintermediate unit, supporting wheel means mounted for steering atopposite ends of each of said units, steering means between thecooperating ends of said units in the form of a tongue pivoted on avertical axis to each cooperating end of each unit, bar means pivoted atits ends on horizontal axes to the tongues of adjacent units, steeringrod means pivotally connecting each tongue of each unit with theadjacent supporting wheel means of each unit, a steering rod couplingmeans interconnecting the supporting wheel means at opposite ends ofeach unit for steering said last mentioned wheel means in unison when aprior conveyor unit deviates laterally from a path of travel and itstongue actuates the adjacent tongue of the following unit.

2. The structure of claim 1 which also includes control steering meanson each end unit to steer the wheels of said end unit in traveling theflexible conveyor in opposite directions.

References Cited in the file of this patent UNITED STATES PATENTS1,658,203 Karlsson Feb. 7, 1928 2,338,704 Clarkson Jan. 11, 19442,420,009 Osgood May 6, 1947 2,525,555 Manierre Oct. 10, 1950 2,633,974Jackson Apr. 7, 1953 FOREIGN PATENTS 5,102 France Oct. 25, 1904(Addition to original Patent No. 344,112)

488,041 Great Britain June 20, 1938 370,224 Italy Apr. 11, 1939 611,784Great Britain Nov. 3, 1948

